UNSHAR V1.2(1)      UNIX Programmer's Manual       UNSHAR V1.2(1)



NNAAMMEE
     unshar - extracts files from shar archives

SSYYNNOOPPSSIISS
     unshar {-overwrite} {-nosort} file1 file2 ...

DDEESSCCRRIIPPTTIIOONN
     Unshar is a utility which extracts files from the ubiquitous
     Unix shar archives. It has the following advantages over
     existing unshar utilities:

          - Small and fast
          - Handles many cat and sed formats
          - Allows extraction of subdirectories
          - Understands ./file type filenames
          - Understands file continuation with >>
          - Sorts file list by Subject: line
          - Exits cleanly with CTRL-C

     The total code size is slightly under 5K, for those with
     packed C directories. It treats quotes and imbedded escape
     sequences intelligently and handles all the cat and sed for-
     mats I've ever seen, including sed commands which strip off
     more than one letter. There may be some formats it won't
     handle, but I've yet to find them.

     Invoke unshar with as many archive filenames as you like.
     All the files in each archive will be extracted into the
     current directory. If a file already exists, unshar asks you
     how you want to handle it. Entering `Y' will overwrite the
     existing file with the version in the archive, `N' will skip
     past the file without extracting it, and `A' will overwrite
     this file and any other existing files without prompting you
     again. Including the -o flag on the command line causes
     files to always be overwritten.

OOPPEERRAATTIIOONN
     Unshar scans through each archive specified on the command
     line, looking for lines beginning with `cat' or `sed'. All
     other lines are ignored. In particular, `echo' lines are not
     echoed. This way, you don't get a load of messages which are
     in any case fairly meaningless, because the operations they
     are describing are unsupported.

     When a shar archive contains a file for which a full path-
     name is given (as in source/file.c for example) unshar will
     create whatever directories are necessary. It also strips
     off leading /'s and ./'s, to make filenames understandable
     by AmigaDOS.

     Occasionally, a shar file distribution will contain a file
     too large to fit into a single shar archive (archives are



Printed 1/22/90     AMIGA Programmer's Manual                   1






UNSHAR V1.2(1)      UNIX Programmer's Manual       UNSHAR V1.2(1)



     typically limited to around 60K or so for transmission over
     Usenet). One method some archivers use to get around this is
     to split the large file into several smaller parts, and use
     the shell `>>' redirection operator to concatenate the parts
     together while extracting the files. In order for this to
     work properly, it is important that the archive files are
     extracted in the correct sequence; otherwise, all the pieces
     will get joined together in the wrong order.

     To assist with this, unshar does a prescan over all the
     files listed on the command line, and checks each file for a
     "Subject:" line. If it finds such a line, it scans it look-
     ing for any hints as to where the file comes in the
     sequence. Most shar files you feed to unshar will be
     directly from a Usenet sources or binaries group, and will
     include a volume and issue reference on the subject line. If
     unshar can't find such an issue reference, it will look for
     a Part number and use that instead.

     Unshar then extracts the archives starting with the lowest
     numbered file. This helps to ensure that those extra-large
     files are created correctly. You can tell when such a file
     is being created, because unshar says "Extending file"
     rather than "Unsharing file".

     If for some reason you want the files to be unarchived in
     the order listed on the command line, you can specify the
     `-n' (nosort) switch, and no sorting will take place.

DDIISSTTRRIIBBUUTTIIOONN
     Unshar may be freely distributed, as long as no charge is
     made for doing so.

HHIISSTTOORRYY
     V1.0@ @ First release.

     V1.1@ @ Added support for some more unusual uses of sed.
           Increased speed, and reduced size slightly.
           Fixed bug that truncated lines longer than 80 chars.

     V1.2@ @ Added support for sorting by Subject: line
           Added support for file appending via >>
           Fixed small bug in detection of disk write errors

AAUUTTHHOORR
     Eddy Carroll
     EMAIL: ecarroll@@vax1.tcd.ie

     Apple //gs port by Andy McFadden (fadden@cory.berkeley.edu).
     Does not presently support wildcards in filenames.





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